The present invention relates generally to concrete paving and paving repair machines and, in particular, to a narrow gauge road repair apparatus.
Concrete road paving machines are well known. Concrete roads are typically paved utilizing fixed form paving methods or slipform paving methods. Fixed form paving methods are typically manual in nature and utilize wood or concrete forms to help the concrete achieve its desired shape. Slipform paving methods, utilizing slipform paving machines, are preferred. Slipform paving machines do not require a wood or concrete form for the concrete and are commonly self-propelled. A typical slipform road paving apparatus includes a frame, a means of self-propulsion, an auger for extruding the concrete mixture, a roller for smoothing the concrete mixture after extrusion, and a vibrating apparatus or tamper to help consolidate the concrete and ease the progress of paving by making the concrete more fluid.
A common practice for paving roads is to utilize these prior art fixed form paving methods or slipform paving machines to lay parallel lanes of concrete paving material typically corresponding in width to traffic lanes. The parallel lanes are connected at a longitudinal joint known in the art as the centerline, which is then treated with a sealant. A common problem is that the centerline often cracks and requires repair much earlier than the remainder of the road because the centerline is the weakest link in the road and allows for the introduction of moisture and incompressible materials regardless of the type of sealant used. Cracks requiring repair also occur along longitudinal expansion saw cuts for the same reasons outlined above.
To address these problems and in an effort to keep road repair costs low, many transportation agencies responsible for road repair are choosing to repair just the damaged pavement surrounding the centerline, rather than the more expensive and time-consuming choice of replacing the entire roadway. A damaged portion of each parallel lane adjacent the centerline is removed and replaced with new concrete. Typical slipform road paving machines are not suited for this type of repair because the width of the paving section is generally two feet, much less than that of prior art machines designed to pave a whole roadway or an entire lane. As a result, the repairs must be done manually, which is both expensive and time-consuming. When repaired manually, only approximately 300 feet of roadway can be repaired per day.
It is desirable, therefore, to provide a road repair apparatus for paving narrow gauge sections of a road and, in particular, to provide a road repair apparatus for use in centerline longitudinal joint removal and replacement operations.
The present invention concerns an apparatus for paving a narrow gauge trench in a concrete roadway. Preferably, the paving apparatus is utilized in centerline longitudinal joint removal and replacement operations. The paving apparatus according to the present invention includes an elongated frame having opposed ends. The frame includes a generally horizontal lower portion having a front wall and a rear wall extending upwardly therefrom, forming an open upper end and having a generally V-shaped cross section. A hopper is attached to the open upper end at one of the opposing ends of the frame. A concrete dispensing aperture extends through the lower portion of the frame at the other opposing end of the frame. An auger is disposed in and extends along the length of the a frame. The auger is rotatably attached to the opposing ends of the frame. A generally V-shaped strike-off member that is shaped to the width of the narrow gauge trench is attached to and extends downwardly from a lower portion of the frame adjacent the dispensing aperture. A roller is attached to and extends downwardly from a lower portion of the frame adjacent the strike-off member and extends rearwardly from the strike-off member. Preferably, the frame is adapted to be attached to a backhoe, tractor, or other type of vehicle having a power take-off that is operable to supply pressurized hydraulic fluid to a hydraulic system on the apparatus. The hydraulic system is the prime mover for the auger, and also controls the operation and orientation of the strike-off member and the roller through various pumps, valves, and rams.
In operation, the apparatus is attached to the vehicle, the hydraulic system is pressurized and a concrete mixture is introduced into the hopper at one end of the frame. The concrete mixture is moved toward the other end of the frame by the auger. The auger also maintains the proper mixture and keeps the concrete mixture flowing. The operator of the vehicle maneuvers the strike-off member adjacent the previously prepared trench and orients the dispensing aperture, the strike-off member, and the roller to a desired location. The concrete mixture exits the frame and is poured into the trench through the dispensing aperture. As the operator moves the vehicle forward along the longitudinal axis of the trench, the strike-off member directs the concrete mixture into the trench and moves any excess concrete further along the trench and the roller smoothes the poured concrete mixture in the trench when it passes over the poured concrete. The operator of the vehicle can advantageously change the orientation of the dispensing aperture, the strike-off member, and the roller as well as the operation of the auger and the roller during operation of the apparatus depending on the requirements of the paving. The operator of the apparatus controls the forward speed of the vehicle, the orientation of the strike-off member and the roller as well as the operation of the auger in order to fill the trench with the proper amount and location of the concrete mixture.
The apparatus according to the present invention is advantageously lightweight, portable, and inexpensive because it is operable to be attached to many types of vehicles and is not self-propelled. The apparatus allows narrow gauge trenches to be quickly and inexpensively paved. Utilizing the apparatus according to the present invention, approximately 6000 feet of roadway can be repaired per day. The apparatus provides a lightweight and portable means for paving a narrow gauge trench in a concrete roadway.